66699666 has 32 divisors (see below), whose sum is σ = 161697600. Its totient is φ = 20211840.

The previous prime is 66699649. The next prime is 66699667.

66699666 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is a zygodrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (66699667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55551 + ... + 56738.

It is an arithmetic number, because the mean of its divisors is an integer number (5053050).

Almost surely, 2^66699666 is an apocalyptic number.

66699666 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

66699666 is an abundant number, since it is smaller than the sum of its proper divisors (94997934).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66699666 is a wasteful number, since it uses less digits than its factorization.

66699666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112311 (or 112305 counting only the distinct ones).

The product of its digits is 3779136, while the sum is 54.

The square root of 66699666 is about 8166.9863474846. The cubic root of 66699666 is about 405.5470248729.

The spelling of 66699666 in words is "sixty-six million, six hundred ninety-nine thousand, six hundred sixty-six".